Model 840 Operating Manual Ver1.0

MODEL 840 POCKET DOPPLER

Before You Begin, Please Read This!

Information contained in this operating manual is provided to help the user operate the instrument controls. In no way must a diagnosis be made on the basis of information provided in the manual. We provide generalized examples of procedures which we believe to be in current usage. However, the procedure to be used and the diagnosis of an individual patient must be determined by the attending physician from information in scientific literature and from other medical sources.

UNDERSTANDING AND USING THE MODEL 840 POCKET DOPPLER The Model 840 Doppler was developed for vascular surgeons to carry in their pockets during rounds. The Doppler is small and relatively inexpensive. In the hands of someone who knows how to use it and knows its limitations, it does a fine job. The best diagnostician I have ever known used the Model 840, even for obstetrics. He could hear things I could not hear, and he proved his diagnosis at the operating table, despite contrary opinions from other surgeons. Because of the Doppler’s low cost, it has found its way into other services where users are not highly skilled in its use, or perhaps are trying to use it in a manner not intended. Its intended service is usually simply making blood pressure measurements on the limbs. I will discuss the limitations of pocket Dopplers and give some usage techniques. LIMITATIONS OF POCKET DOPPLERS: The circuitry and probe used in a pocket Doppler are about the same as that used in a larger unit. The difference between the two is primarily the battery power available. If the instrument is a convenient small size, a small battery must be used. If a lot of power is drawn from the battery, it will run down sooner. To get really good performance, you have to take a comparatively large amount of power from the battery, so one has to compromise. Use a moderate size battery, readily available, and use a moderate amount of power so you do not have to replace the battery frequently. That is what we have done in the Model 840. However this size of instrument has less penetration and a smaller ultrasound beam than a larger unit. Also you must use earphones instead of an internal speaker. You will note that the probe on the end of the case has two small rectangular crystals, they vibrate at about 8 million times a second. One is sending in a continuous beam of ultrasound, the other is receiving the reflection. So the size of the ultrasound beam is about the size of one of the crystals, though it does enlarge some as it goes into the tissue. Compared to a competitor’s Doppler with bigger crystals, placement must be more precise. However, if you want to hear flow in a finger or toe, the supraorbital artery, or separate an artery from the adjacent vein, our instrument is superior. The frequency used is 8 Megahertz (vibrations of approximately 8 million times a second). To obtain an audible signal that stands out well above the background noise (which all Dopplers have), you have to push in toward the artery. You will receive better signals if you angle the beam upstream. There is an angle built into the front of the case to aid you in aiming the probe. You should lay the angled part of the case about flat against the skin. For a deeper vessel you will have to tilt the back of the unit more toward perpendicular. However, perpendicular works poorly with this type of probe. Always angle into the flow and IN LINE with the flow.

Parks Medical Electronics, Inc.

Model 840

Ver 1.0

UNDERSTANDING AND USING THE MODEL 840 POCKET DOPPLER In some places along the posterior tibial there is anatomical hiding of the vessel from muscle or tendons. That is why you should move up or down the vessel a little to find the best signal above the background noise. Keep in mind that the accuracy of a blood pressure measurement is dependent on having a proper width cuff for the area on the limb you are measuring. The function of the Doppler is to let you know weather or not blood is flowing under the cuff. To know that you MUST have the probe directly centered over the artery and not move it while inflating the cuff. BATTERY: As the battery runs down, the signal will get weaker to the point where the instrument will not function. Most batteries run down because the instrument was left on. You only need less than a minute to make a blood pressure measurement, so turn the unit off immediately after you take it off the skin and BEFORE you take off the headphones. Use an alkaline-type replacement 9-volt battery. Never use a mercury battery. THE COUPLING GEL ____________________________________________________________ YOU MUST USE GEL IN FRONT OF THE PROBE. We recommend you use a coupling gel made especially for ultrasound. Don’t use a gel that is too runny. You can use sterile jellies internally. Ultrasound coupling gels are available from us, or will usually be available from one of your surgical supply dealers. These gels are available in bulk, sterile packets and bottles. Gel in a semi-rigid tube with a small extended tip is easier to use than that which is in collapsible tubes. Refilling from bulk is much less expensive than buying more bottles or packets. Some tubes can be autoclaved. PLEASE DO NOT USE ECG PASTE OR CREAM. THE RED PROTECTIVE COVER MUST BE REMOVED FROM THE PROBE BEFORE USE.

WA R N I N G : T H I S D O P P L E R I S I N T E N D E D F O R U S E B Y H E A LT H C A R E PROFESSIONALS ONLY. This Doppler may cause radio interference or may disrupt the operation of nearby equipment. It may be necessary to take mitigation measures, such as reorienting or relocating the Doppler, or shielding the location. PHYSIOLOGICAL EFFECTS OF ULTRASOUND _______________________________ IMPLANTED DEVICES Implanted devices such as cardiac pacemakers should be avoided due to the possibility of affecting their operation. Also some plastics used in replacement surgery may be affected by absorption of ultrasound energy. Metal implants may lead to reflections and as a precaution, avoid using ultrasound close to these. STUDIES NEAR SENSITIVE TISSUES Extreme care should be taken when treating areas near the eye because of the danger of damage to the retina. Similarly, extreme care should be taken near other sensitive nervous tissue. Based on experimental and epidemiological data, there is presently no identified risk associated with diagnostic ultrasound. However, a prudent and conservative approach is recommended in which diagnostic ultrasound should be used only for medical benefit and with minimal exposure. Parks Medical Electronics, Inc.

Model 840

Ver 1.0

OPERATING INSTRUCTIONS MODEL 840 USE OF THE PENCIL PROBE IN THE DIAGNOSIS OF ARTERIAL DISEASE IN THE LIMBS

1. THE PROBE. The probe consists of two crystals; one for transmitting the ultrasound waves and the other for receiving the reflected waves. If either crystal is damaged, the probe will not work properly or will not work at all. The crystals are covered by a material that is vulnerable to attack by heat, alcohol and ECG paste or cream. Therefore, DO NOT use ECG paste as the contact medium between the skin and the probe. Use AQUASONIC or any gel made for ultrasonic physical therapy equipment. In an emergency use any surgical jelly or lubricant, even petroleum jelly or mineral oil. Remove the gel after use with a soft tissue. If you should find the probe with dried gel on it, wash it off under running water. Do NOT scrape off the gel because you may damage the coating over the crystals. 2. POSITION OF THE PROBE: Invariably, people not accustomed to our probe use it incorrectly. The probe we furnish is different from that of the other manufacturers and is used differently. If you hand someone the probe and say “Here, try it for yourself”, they will almost always put it over their radial artery and place the probe perpendicular to the artery-and perhaps with no coupling gel. Many people have tried to compare our Doppler with other makes by this method. Keep in mind that you are not buying a Doppler for use on the radial artery, but for use on vessels you cannot feel. The best testing ground is therefore in your particular area of interest. We believe our instruments will permit you to find the vessels easier, let you hear the venous sounds easier and follow the vessels better than any other device on the market, regardless of price. But it takes some practice in order to be able to do this. We believe the arm is a good and most convenient limb for you to learn on-to learn how to hold the probe depending on the depth of the artery and vein. The area about 6 inches each side of the elbow is a good place to start. First, put some gel on the tip of the probe. The gel squeeze-bottle must be shaken downward and then gently squeezed to get the gel to come out. Pile up about a quarter of an inch of gel on the probe, making certain there are no large air bubbles in the pile because ultrasound does not go readily through air. It needs a continuous conducting medium, and the gel is ideal. Turn the VOLUME control fully down (counter clockwise) and turn the instrument on. Gradually turn up the volume. You should hear a rumbling sound if you are holding the probe. This is caused by the vibration of the gel due to tremor in your arm. Now place the probe over an artery in the arm about half way between the elbow and the wrist. Tilt the back of the probe toward the hand at an angle of about 45 degrees, making certain there is gel in the pathway between the probe and the skin. Move the probe and the skin sideways to try to find the center of the artery and the hissing noise at heart rate, which is the Doppler sound for an artery. If the sounds you hear are more or less continuous, that is simply the background noise of the instrument and it means that you are not over the artery. The main energy of the beam is only about as wide as the crystals in the probe, so there isn’t much room for error in aiming the probe. For this reason you must always search the area of the artery and tilt the probe for best Doppler sounds.

Parks Medical Electronics, Inc.

Model 840

Ver 1.0

OPERATING INSTRUCTIONS MODEL 840 When you are looking for deep arteries, or for small or obstructed arteries, you will have to turn the VOLUME control near maximum. This also means that every time you move the head of the probe you are going to get some pretty big thumping noises in the earphones. Therefore you want to avoid moving the head of the probe with respect to the skin as much as possible. That is why you place the probe over the area where you think the artery is and then you search for the exact point by moving the skin with the probe and changing the angle of the probe with respect to the skin. You might wonder why these big transient noises can’t be filtered. We do limit their intensity, but we do not filter. The reason is that in the search for low-velocity blood flow, such as in occluded arteries and in the veins, the pitch of the Doppler sounds associated with the blood flow are very low. Any filtering to eliminate or minimize the sounds accompanying movement of the probe would also reduce the response to low-velocity blood flow sounds, and of course this is undesirable. 3. DIAGNOSIS OF ARTERIAL DISEASE: The Doppler method of diagnosing arterial disease of the limbs is only one of several good methods. It is probably the most convenient and least expensive of the better methods. It is only qualitative but can be made semi-quantitative by permitting you to make systolic blood pressure measurements along the leg with the aid of a proper cuff and manometer. The great sensitivity of the transcutaneous Doppler can cause a doctor or technician to conclude improperly that an arterial pathway is open when it isn’t. Collateral flow around an obstruction can be well-developed, especially in the thigh, and cause pulsatile blood to flow in the distal arteries. Or a major artery may be narrowed, causing pulsatile flow distally. These mistakes in diagnosis can be avoided almost entirely by simple means and a little bit of experience. An experienced user of the Doppler can recognize the characteristic sounds of open and obstructed arteries. Remember that Doppler sounds vary in pitch (frequency) with the velocity of blood flow. When you hear the Doppler sound on a normal artery and compare it with a normal arterial pulsepressure wave, you will recognize the sound of the dicrotic notch, the very fast rise time of the wave and perhaps a third sound just before the onset of a new pulse wave. While the origin of these second and third waves in the descending branch of a pulse wave may be in dispute, their absence in vessels distal to an obstruction is not disputed. So a diagnostic rule is that whenever you hear the second and perhaps third sounds of a pulse wave of a major artery, you can be sure the artery is open proximal to the probe. Plethysmographic studies also show a delayed crest to the wave, associated with a slower rise time to the wave when there is an obstruction proximally. Though the Doppler is permitting you to hear velocity changes rather than true volume changes, the correlation is good enough to be quite valuable diagnostically. Now the opposite is not necessarily true-that when you can’t hear second and perhaps third sounds the artery is obstructed proximally to the probe. In the digits and smaller vessels the pulse wave is smoothed out more, especially when there is some vasoconstriction. Now of course there are cases that are in doubt. If you cannot clearly hear the second and third sounds (the third sound is frequently missing), compare with the same artery on the other limb. If you find a radical difference in the sound of the Doppler, both in pitch and in amplitude, you are justified in being quite suspicious of the patency of the artery of the first limb you studied provided you are now fairly skilled at optimizing the sounds. Parks Medical Electronics, Inc.

Model 840

Ver 1.0

OPERATING INSTRUCTIONS MODEL 840 Another thing you listen for is the relative clarity of the arterial wave. How well it stands out from the background noise of the instrument and perhaps the venous flow adjacent to the artery. Move the probe a little to each side of the artery to make this estimation. In a normal person you will find that you can make the arterial pulse wave almost completely separate from the venous sounds by positioning of the probe. The way you really come to a final conclusion that the artery is obstructed proximal to the probe is by measuring the systolic pressure at the ankle with an ordinary arm cuff. If you want to measure pressure at other places on the leg you will need a special cuff, the bladder of which encircles the limb. We sell such cuffs. The method is as follows: Wrap the cuff around the ankle or slightly above it so you can get the probe on the posterior tibial and hear the arterial sounds adequately. Inflate the cuff to a pressure well above the patient’s arm pressure or at least 30 points above the pressure at which the Doppler sounds disappear. Gradually reduce cuff pressure until you hear blood flow, though the sound won’t be normal. At that point read the pressure to obtain systolic pressure at the ankle. If you have doubts, center the probe on the artery and inflate the cuff again. You can observe at what cuff pressure the blood flow stops and again where it starts. Where it starts is normally used. This procedure is very similar to taking pressure on the arm using a stethoscope. There you are using sounds of turbulence or wall motion. Here we are sensing the flow of blood under the cuff with a much more sensitive device. You can get a clear indication of systolic pressures as low as 30 mm. of Hg. The only problem is keeping the probe right on the center of the artery while you are inflating and deflating the cuff. An aneroid manometer mounted on the inflation bulb of the cuff is preferable. Tycos makes such a device and perhaps others do too. The possibility of misdiagnosing is greatly reduced by this method provided you make two or more measurements and you are skilled at holding the probe in the right place and at the right angle. A low pressure reading is quite reliable. On diabetics you may get readings of 300 mm. Hg. or more, even though they have ulcers on their toes. These people with end-artery disease studied plethysmographically with the mercuryin-silastic strain gage, which we also make, will have quite large and normal looking pulsations in the toes. Their arterial walls are sclerosed so badly sometimes that they will not compress with cuff pressure. The normal pressure in the ankles should be about the same as the systolic pressure in the arm, or a little higher. If the ankle pressure is 30 mm or more lower than the arm pressure, an obstruction is almost certainly present. Normally one finds that people with arterial obstructions have pressures of 100 or less. If you have a proper cuff you can take pressures in the same manner (with the probe at the posterior tibial) just below the knee, just above it and at the top of the thigh. By measuring systolic pressure (the pressure measurement is always where the cuff is, not where the probe is) you will find radical differences between measuring sites if the obstruction is between them or you will find that pressures at corresponding points on the two legs are quite different. An exception is bilateral obstruction of the bifurcation of the abdominal aorta which may give you fairly symmetrical pressures on both legs. Unfortunately you cannot use the Doppler above the top of the thigh. The pressure measurements made on the thigh with a narrow cuff will be clinically useful, though not accurate. Parks Medical Electronics, Inc.

Model 840

Ver 1.0

OPERATING INSTRUCTIONS MODEL 840 Once you have determined that there is an obstruction it is often desirable to determine just where it is. It is permissible to check at certain points provided you are quite familiar with normal sounds-second and perhaps third sounds. Start at the top of the thigh and listen for the normal arterial sounds. A little to one side you should hear venous flow varying with respiration. The adjacent venous flow assures you that you are indeed listening to a major artery. This is important because you can get beautiful sounds from a collateral that is aimed toward your probe and giving a tremendous Doppler effect. But a collateral follows a tortuous path and the venous sounds will not be found adjacent to it. If you have a little problem hearing the vein (and you shouldn’t over big veins) give the leg a slight squeeze distal to the probe to increase the velocity of the venous blood and make its pitch higher. As you follow the superficial femoral artery down toward the knee you will lose the sound, even on normals, in some parts of the path because of tendons or other anatomical obstructions between the probe and the artery. You should be able to pick it up again easily in the popliteal region. Your ear and concentration make a filter to extract wanted information from background noise that exceeds anything that can be done electronically. You can follow these small arteries distal to the knee and in some cases they can be followed all the way to the ankle and beyond. Keep in mind that some people don’t have a dorsalis pedis artery. If you are working on arteries in the foot, make sure they are dilated by immersing the foot in a bucket of warm water for a few minutes. Some people are vasoconstricted most of the time. They usually will dilate for a while after the immersion and in a few minutes be constricted again. Also they usually do not have arterial disease. If you want to quickly determine the efficiency of flow in the arterial system of the leg, pick up the posterior tibial and listen for 2nd and perhaps 3rd sounds. If you hear them, and you are sure you know the difference between normal and abnormal, go no further. If they do not sound normal or there is doubt, make a blood pressure measurement and compare it with systolic pressure on the other ankle and on the arm. To find the location of the obstruction you can listen with the Doppler, or using a special cuff you can make blood pressure readings farther up the leg. If the obstruction is in the iliacs you can note it by the Doppler sound distal to the obstruction or by a much lower than normal blood pressure at the top of the thigh as measured with the cuff and the Doppler. PRE-OPERATIVE AND POSTOPERATIVE use of the Doppler is very important. When the patient is on the table, measure systolic pressure at both ankles and record it. After blood is again permitted to flow measure both pressures again. The pressure on the operated leg should be UP compared to the pressure in the other leg, the control. If it isn’t, then it is pretty safe to assume something is wrong. On rare occasions a limb will have such a high degree of reactive hyperemia that pressure will not be up and may even be lower, but the leg will be hot. A large percentage of patients are blocked to some degree before they get off the table. Blood-pressure measurements will give you an objective evaluation of the surgery. Some surgeons use the pencil probe directly on the artery (using sterile jelly for coupling) just distal to the repair. The characteristic of the flow sound is important. If the runoff is inadequate an experienced ear can detect it and often correct the cause on the table. You can also use Doppler and pressure measurements for follow up, comparing pressures at both ankles with systolic pressure at the arm, measured either with a Doppler or stethoscope.

Parks Medical Electronics, Inc.

Model 840

Ver 1.0

USING THE DOPPLER ON DIGITS MODEL 840 Line up the long way of the crystals with the length of the artery for best best efficiency on the digital arteries. Whenever you try to pick up arterial flow from the digits you must consider digit temperature. It is often difficult to get a digital pulse when feet are cold or cool. The digits can be so vasoconstricted that blood only oozes through, which is sufficient to nourish but does not give a good recording or sound on any device. This occurs in perfectly healthy digits under normal conditions. It also occurs after surgery when severe vasospasm may occur. In order to get a good sound or blood pressure measurement under these conditions you must cause vasodilatation to take place. One method is to warm the extremity by immersing it in warm water, not hot water. Within a few minutes you will be able to evaluate the condition of the flow when the limb is at heart level or slightly above. Another method used to dilate peripheral vessels is to occlude all flow at the ankle or forearm with an ordinary arm cuff infrated to well above systolic pressure. This is not normally painful, especially when vascular disease is present in the arterial system. If too much discomfort is apparent, a different procedure could be tried. Five minutes is usually enough time. On release of cuff pressure a reactive hyperemia will take place and last for a short time at least. There should be enough time to make an evaluation of arterial patency. Diabetics may have incompressible arteries so this technique may not work with them. When there are two sounds to the arterial pulse wave, the first caused by the filling of the vessel with systole and the second being either forward or reverse flow in the diastolic phase, vessels are usually patent. However, blockage of major proximal arteries may be present with good collateral flow around them. When there is only one sound with each cardiac cycle and the sound is not brisk, a proximal stenosis or occlusion may be present. PROPER INSTRUMENT PLACEMENT AND PROPER USE OF GEL ARE VERY IMPORTANT!

The instrument body should be in line with the artery, not crosswise to it, and should be at about a 45 degree angle. You must be very careful about pressure, because a slight amount of pressure against the skin will occlude the artery. You must use a dab of gel in front of the probe. You may find it impossible to make blood pressure measurements on the digits with a Doppler, especially the toes. It is better to use our photoplethysmograph for that purpose. Doppler sounds from digital arteries will be very helpful once you become familiar with normal and pathological sounds. Making digital pressure measurements on the toes is not a very popular procedure. Refer to your medical literature for diagnostic procedures. This information is primarily meant to be a simplified guide to the use of the instruments and the probe.

Parks Medical Electronics, Inc.

Model 840

Ver 1.0

TECHNIQUE OF EVALUATING CALF VENOUS DISEASE MODEL 840 The assessment of calf venous disease by Doppler ultrasound may be achieved with an accuracy of up to 85% compared to venography when one is experienced with the technique. The status of the calf veins can be assessed by listening with the Doppler at the posterior tibial vein at the ankle, the popliteal vein, the superficial femoral vein, and the common femoral vein. The status of the calf veins is determined by a combination of augmentation maneuvers when listening at these various points. Normal Respiration Flow Sounds: The Doppler is initially placed over the posterior tibial vein at the ankle behind the medial malleolus. Generous amounts of acoustic gel must be used, and one must be careful to avoid undue pressure with the probe which might result in obstruction of venous flow. Initially the posterior tibial artery signal is elicited. The probe is then moved slightly to either side of the arterial signal until the windstorm like venous signal is heard. Normally this signal should wax and wane with respiration. In the presence of calf vein thrombosis, the signal may be more continuous or there may be no audible signal present. If the feet are vasoconstricted, a venous flow signal may not be heard until the venous velocity is increased by gentle compression of the foot. Checking Competency of the Valves: Once the optimal venous signal is elicited, the calf is then compressed with the hand which is not holding the probe. The fingers should be spread so that much of the calf muscle is compressed. During this procedure, no venous flow should be heard. If venous flow signals are elicited, this is a sign of deep venous valvular incompetence, usually secondary to old deep vein thrombosis. Augmenting Venous Velocity by Compression: Next the calf is released and one should normally hear an augmentation of venous flow as blood enters the previously decompressed calf veins. The magnitude and duration of the augmented signal can be influenced by several factors including the temperature of the foot, the general vasomotor tone of the patient and the presence or absence of venous thrombosis in the calf. It is important to compare the augmentation signals in each foot. In vasoconstricted individuals with cold feet, the posterior tibial venous augmentation may be very minimal but it should be symmetrical. If there is good augmentation in one leg and poor augmentation in the other, the latter leg is usually the site of venous thrombosis. Next, the common femoral and then the superficial femoral veins are examined and the signals assessed for augmentation upon calf compression. Calf-vein thrombosis will result in a decreased augmentation of the venous signals at these sites. Similarly the popliteal vein should be examined. In general, the most sensitive indicator of calf-vein thrombosis is a relative decrease in augmentation upon release of calf compression with the probe positioned over the posterior tibial vein at the ankle. There are certain conditions which will imitate calf-vein thrombosis. Such problems as subfascial hematoma, a ruptured Baker’s cyst, extensive edema, or other conditions which cause increased pressure on the calf veins may result in a decreased augmentation of flow during the aforementioned maneuvers. Such conditions can be best diagnosed by a venogram if the diagnosis is in question.

Parks Medical Electronics, Inc.

Model 840

Ver 1.0

STRANGE NOISES FROM THE DOPPLER MODEL 840 On occasion there are noises you might not expect from the Doppler when in fact the Doppler is working fine. The following are some common concerns and their causes.

Concern:

Remedy:

Cause:

Popping scratchy noises sounds when the probe is first placed on the skin.

Air bubbles in the gel are moving and/or popping. Hair movement can also cause these noises.

Use a new dab of gel that looks clear, push the probe down enough so hair is immobilized, and wait a few seconds for everything to settle. If the noise is not there when the probe is clean (no gel) and suspended in the air, the Doppler and/or probe are probably working fine.

Static when the dry probe is moved through the air.

Possibly loose connectors internally, where the probe connects to the instrument.

There is normally some static generated when the instrument is moved through the air without gel on the probe, but it isn’t severe. Have the probe replaced or contact the factory if the problem persists.

High pitched tone.

Radio interference from a mobile service, police station nearby, even another Doppler working close by. Usually occurs near large open windows, rarely in the center of the building.

Move the Doppler to another location away from windows and toward the center of the building. If the problem persists contact the factory.

Buzzing noise that almost obliterates the Doppler signal.

Electrocautery or other sparking device, bad fluorescent light fixture or neon signs nearby.

Move the Doppler to another location away from the interference. If the problem persists contact the factory.

Howling noise when probe is held or laid on a table with gel on it.

Probe is acting as a microphone and you are getting acoustic feedback.

Wipe gel from probe, If the noise does not occur without gel on the probe, it is probably working fine.

SUMMARY: The problem may simply be a probe or it may be peculiar to the environment in which it is used. If you have tried the tests and remedies mentioned and you still suspect a problem contact the factory toll-free at 1-800-547-6427.

Parks Medical Electronics, Inc.

Model 840

Ver 1.0

BATTERY REPLACEMENT MODEL 840 TO CHANGE THE BATTERY:

Be sure the Doppler is turned off. Remove the Doppler from its case by unthreading the screw in the end of the case while putting light pressure against the probe as shown. This pressure will push the Doppler out of the case as the screw is loosened. The screw need not come all the way out of the case.

Pull the battery out of the Doppler and remove the snap-on cover by pulling on the cover, not the wires. Note that the terminals on the battery are different. Match the snap fasteners on the battery to the appropriate ones on the cover so the cover will snap onto the battery. Put the battery in place, slide it into the case gently, making sure the probe is coming through the large hole in the end. Use gentle pressure on the front panel of the Doppler and tighten the screw you loosened before. Be sure the panel is fitting itself properly into the case as you tighten the screw.

FOR BETTER PERFORMANCE ALWAYS USE A 9 VOLT ALKALINE BATTERY.

When the sound gets weak or distorted, the battery should be replaced. CAUTION: Never use mercury batteries!

Battery must be recycled or disposed of properly. Parks Medical Electronics, Inc.

Model 840

Ver 1.0

Diagnosis and Treatment of Chronic Arterial Insufficiency of the Lower Extremities HOWARD C. BARON, M.D., F.A.C.S.*

Leg distress -- cramps, fatigue, or just vague pain -- often signal the presence of a peripheral vascular disease. It could be arterial -- the first sign of arteriosclerosis obliterans. Simple office evaluation, including the patient’s description of leg pain, and an examination of the affected limbs, will often give a clear picture of the underlying vascular problem -- where it is, how extensive it is, which vessels are involved, and how adequate is the collateral circulation. A typical patient with arteriosclerosis obliterans, the most common of the arterial occlusive diseases, develops pain in one or both legs that requires him to stop and rest after walking a short distance. He may call it a cramp, a charley horse, or it may be just a feeling of tiredness in the limb after walking a certain distance. An elderly patient often admits to having calf pain for months or sometimes years with “no reason to mention it since aches and pains are bound to occur as you grow older.” However, where he previously could walk 4-5 blocks before the calf pain occurred and made him stop, he’s concerned because the pain now occurs after walking only a block or so. Arterial occlusive disease due to arteriosclerosis obliterans, is insidious in onset and often present in a patient for many years before any ischernic symptoms occur. Rarely will anyone complain of intermittent claudication, the most commonest symptom of arterial occlusive disease, while indoors. However, walking outdoors causes the pain to occur. There is a typical pattern to this symptom of limb ischemia; exercise -- pain -- rest -- relief. Patients characterize the pain of intermittent claudication in various ways. One will describe it as a sensation of cramping or tightness, “as if the leg is in a vise”. Another will describe increasing fatigue eventually forcing the patient to stop walking and rest. However, in all of these patients, resting for a few minutes is sufficient to relieve the pain If the need to sit down or elevate the extremity is a feature of a patient’s complaint, or if it takes more than a few minutes for the pain to abate, suspect a disease process other than arterial insufficiency as the cause of the pain.

As the disease progresses a different type of pain occurs in the toes or heel. Termed rest pain or night pain, it is an ominous symptom of advanced arterial occlusive disease due to multisegmental blocks in the major limb arteries and an inadequate collateral circulation around these blocks. This pain characteristically occurs in the distal portion of the foot, the toes, over the dorsum of the foot, in the heel area, or in the region of the metatarsophalangeal joint. The patient describes the pain as a severe ache or throbbing which often wakes him after several hours of sleep. Relief is sometimes obtained by rubbing the affected foot or placing it in a dependent position over the edge of the bed. Elevating the limb often increases the pain. In some patients, relief is afforded by sleeping in a chair with the leg in a dependent position. Leg pain and even “pseudoclaudication”, a form of leg pain that can mimic true intermittent claudication, can occur with a variety of processes other than arteriosclerosis obliterans such as degenerative disorders, for example, osteoarthritis of the hip of spondylolysis. Compression of the cauda equina also can produce claudication-like symptoms. In t h e s e patients, the typical cycle of exercise-pain-rest-relief is not present. The presence of normal pulses in the leg and a normal ankle systolic blood pressure aids in distinguishing the pain of pseudoclaudication from arteriosclerosis obliterans. Examination of the affected foot yields a great deal of information. Skin color, texture, and consistency all depend on arterial blood flow and can indicate the presence of an impaired circulation. If the patient has only mild, generally asymptornatic occlusive arterial disease, the color and nutrition of the leg and foot appears normal. As the ischemic process becomes more severe, the skin appears shiny and smooth, and hair is often absent from the toes and the dorsal region of the foot. Muscle atrophy, loss of subcuataneous fat, and pallor all indicate a severe degree of ischernia.

A fairly simple and accurate clinical test that can measure the degree of arterial insufficiency in the affected leg is the elevation-dependency maneuver performed while the patient is on the examining table. With the patient lying on his back, place his heels in the palms of your hands and elevate both legs 24-36 inches off the table. Hold the legs in this position for at least 45-60 seconds. Observe the color of the feet and legs, particularly the soles of the feet. If the arterial circulation is normal the skin coloration will decrease only slightly. Skin pallor will develop in the affected limb according to the degree of arterial insufficiency. If pallor occurs in both feet suspect either an arteriosclerotic block in the abdominal portion of the aorta or similar blocks in the major limb arteries. After the period of leg elevation, generally no more than several minutes, have the patient immediately stand up. In a patient with normal arterial circulation in the legs, color will return to the foot in 10 seconds or less, and the superficial veins in the distal portion of the foot will fill in 10-15 seconds. If arterial insufficiency is marked, the normal color may take 40-60 seconds to return; in severe cases more than 2 minutes. Reactionary rubor of the foot (a burgundy red color) may occur after the limb becomes dependent; this indicates the presence of advanced limb ischemia and often portends ulceration and “ gangrene of the foot”. An absent or greatly diminished pulse is a diagnostic finding of major importance. The presence of a pulse however, does not always indicate a normal arterial flow; its absence is far more significant. In a patient who complains of intermittent claudication and has palpable resting pulses, don’t discard the diagnosis of arteriosclerosis obliterans without investigating the “disappearing pulse” phenomenon. Have the patient exercise until he experiences claudication; examination of the ankle pulses may then reveal an absent pulse associated with leg pallor. The physiologic explanation is simple: exercise causes a marked dilation of the arteriolar beds within the exercising muscles. During exercise blood is shunted to these muscle groups causing a drop in the ankle systolic blood pressure which is distal to the site of the arterial block. As the ankle systolic blood pressure falls, the distal pulses disappear. Except when life expectancy or surgical risk

contravenes due to other systemic diseases, angiography and surgical revascularization is indicated for all patients with symptomatic arteriosclerosis obliterans exhibiting cutaneous skin changes, such as ischernic ulcers or gangrene; the presence of rest pain or intermittent claudication that handicaps the patient economically or socially. Angiography is necessary to evaluate the extent of the arterial lesion. Typical arterial lesions due to arteriosclerosis obliterans are segmental, occurring in areas of branching, narrowing, or bifurcation sites of an artery. The commonest occurring at the bifurcation of the aorta, or the iliac and femoral artery divisions. Another frequent site is the distal superficial femoral artery as it emerges from the adductor canal of Hunter and the distal popliteal artery as it branches into the anterior and posterior tibial and peroneal arteries. Certain patients are not candidates for angiography; these include the elderly patient with moderate disability and associated cardiac disease, and generally any patient with the presence of another life-threatening disease. A satisfactory angiographic study provides a visual study of the anatomic lesion, indicating the extent of the lesion and to a degree its severity. The angiogram, however, does not yield information regarding the hemodynamic significance of the lesion. For this information the Doppler flow detector is a useful and accurate instrument. The importance of the ankle/arm systolic blood pressure ratio in the diagnosis and objective assessment of arterial disease underscores the value of the Doppler ultrasound blood flow detector. Although the auscultatory method with a stethoscope is one of the most common blood pressure measurements in clinical medicine, it is seldom used in the lower extremity because it is difficult to obtain the Korotkoff sounds in the distal portion of a limb, especially when arterial occlusive disease is present. The Doppler flow detector, when used with a sphygmomanometer and a pneumatic occlusion cuff, can measure the lower extremity systolic blood pressure easily and accurately. Normally, the ankle systolic blood pressure is slightly higher than the arm systolic

blood pressure. Any pressure gradient or difference that exists between the arm and ankle systolic blood pressure provides a valuable, objective hemodynamic assessment of the arterial lesion. Certainly, the lower the ankle systolic blood pressure when compared to that in the arm, the greater the gradient and therefore, the more advanced the arterial occlusive lesion in the distal abdominal aorta or lower extremity arteries. Two of the most important aspects of managing patients with Arteriosclerosis obliterans are the need to avoid any form of injury to the affected foot, this includes the avoidance of any form of home surgery on the feet, and the avoidance of tobacco smoking. A recent study of ours indicates that 40 percent of major lower extremity amputations might have been avoided by taking simple precautions against infections stemming from mechanical, thermal, or chemical injuries to the feet. Meticulous, periodic, podiatric care is necessary for any foot with an impaired circulation with its known increased susceptibility to infection. Even fungal infections such as athlete’s foot can put the ischernic foot at serious risk. Certain over-the-counter pharmaceutical preparations for removing corns and calluses that contain caustic chemicals can be harmful to surrounding tissues, especially when used in the presence of an impaired circulation and should be avoided! Thromboendarterectomy of the occluded artery or the use of bypass grafts are the operative procedures most frequently used for revasculatization of the ischernic limb. Sympathectomy may be helpful in certain patients, but is rarely considered for patients who are candidates for arterial surgery and it is not recommended for treatment of intermittent claudication. However, minor ischemic ulcerations may heal and rest pain may occasionally be relieved following sympathectomy. A limited number of patients with advanced arteriosclerosis obliterans may show improvement over periods of weeks from non-surgical measures including rest, the use of vasodilators, and avoidance of tobacco smoking, permitting the development of an

additional collateral circulation. However, the long period before results can be evaluated is risky: gangrene may supervene calling for emergency surgical reconstruction of the occluded vascular bed if amputation is to be avoided.

CONCLUSION There are both humanitarian, economic and social reasons for mounting a strong effort to salvage the lower limbs in patients, who are often elderly, and debilitated, but obvious candidates for a revascularization procedure. The physical, psychological and economic burdens following amputation preclude a useful or comfortable life in the years remaining to them. Limb salvage, the desideratum of any age, is particularly important in the geriatric patient whose care then places a heavy burden on a spouse of similar age or another family member. A patient confined to a wheelchair or bed is unable to attend to even the simplest personal needs; he often becomes withdrawn from human contacts, psychologically as well as physically damaged. Partial limb revascularization, by saving the extremely valuable knee joint, is often a reasonable alternative, allowing salvage of as much as possible of a limb affected by end-stage ischernia. The goal should be treatment of the disease without loss of the lower limb or, if amputation becomes necessary, a below-knee procedure or even a transmetatarsal amputation, permitting the patient to lead a more normal life. 222 East 19th Street New York, New York 10003

*Attending Vascular Surgeon, Cabrini Medical Center, New York, N.Y.; Associate Professor of Surgery, New York, University School of Medicine, New York, N.Y.

Practical Office Technics for Physiologic Vascular Testing * COL CLYDE 0. HAGOOD, JR., MC, USAF, LTC DAVID J. MOZERSKY, MC, USAF, and SSGT RANDAL N. TUMBLIN, BS, USAF, † Lackland AFB, Tex

Abstract: The development of the Doppler ultrasonic flow velocity detector has improved diagnostic accuracy in peripheral arterial occlusive disease. Survey of the peripheral vessels with the Doppler ultrasonic flow velocity detector, measurement of systolic arterial blood pressure at the ankle and arm, and exercise testing are three easily done tests which may be readily carried out in the doctor’s office and which provide useful information. Noninvasive vascular testing should be in the armamentarium of all primary care physicians.

A therosclerosis of the peripheral vessels is extremely common in our society and is responsible for significant morbidity and mortality. It is therefore imperative that the physician who first encounters patients with vascular complaints recognizes the disease and begins proper treatment. Until recently, the diagnosis of arteriosclerosis obliterans has been dependent upon the clinical history and physical examination. As a result, the disease has only been detectable in a relatively far advanced stage. Since the introduction of the Doppler ultrasonic velocity detector in 1959, more sensitive and objective methods of evaluation have been available to the clinician.1-4 The use of these technics, however, has been restricted to a relatively small number of specialists and investigators. Although they are extremely simple to do, these examinations have not been widely used by primary care physicians. The purpose of this paper is to familiarize clinicians with three simple office technics for detecting atherosclerotic occlusive disease and to present three cases that illustrate the efficiency of these technics. *Read before the Section on Surgery, Southern Medical Association, S i x t y - s e v e n t h A n n u a l Scientific Meeting, San Antonio, Tex. †From the Department of Surgery, Vascular Surgery Service, W i l f o r d H a l l U S A F M e d i c a l C e n t e r, L a c k l a n d A i r F o rc e B a s e , Tex . Reprint requests to CMR #8, Box 369501, L a c k l a n d A F B , Tex 78236 (Dr. Hagood).

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Material and Technics The Doppler ultrasonic velocity detector has become a familiar tool used by obstetricians and vascular surgeons alike.5 The instrument uses two piezoelectric crystals. One crystal, when stimulated by an electric voltage, emits a continuous wave of ultrasonic energy at a frequency of 5 to 10 MHz, which is transmitted through the skin. If this sound wave is reflected back from stationary tissue interfaces, the frequency of the returned signal received by the second crystal will be the same as the transmitted frequency. If the sound wave strikes moving red cells, the returned signal will be a different frequency from the transmitted signal. The difference is directly proportional to the velocity of the blood, according to the Doppler principle. The transmitted and received frequencies are compared electronically and the difference between the two, the Doppler shift frequency, is amplified. Since this frequency is in the audible range, it can be perceived with earphones or a loudspeaker. For most clinical purposes, the audible signal is all that is necessary. Ultrasonic energy transmitted by these instruments has been tested both in the laboratory and clinically and has been found to be non-destructive to tissue. 6 Examination can thus be carried out at frequent intervals without fear of over-exposure. After the routine history and physical examination have been completed, the peripheral vessels are surveyed with the Doppler ultrasonic velocity detector.

OFFICE TECHNICS FOR VASCULAR TESTING - Hagood et al

The quality of the arterial signals is evaluated at the common femoral, superficial femoral, popliteal posterior tibial, and dorsalis pedis arteries bilaterally. If the vessels are patent, these signals will be composed of at least two, and often three, distinct sounds. The first is high-pitched and is distinctly separated from the second (Fig 1, A). When mild proximal arterial stenosis is present, there is a slight decrease in the frequency of the first sound and the second sound is no longer detected (Fig 1, B). As the degree of occlusion becomes progressively more severe and collateralization develops, the signal becomes more monotonous with only small fluctuations with each heart beat (Fig 1, C). These changes in the nature of the arterial signal can be detected easily 5 after gaining some experience with the instrument.

An objective and reproducible determination of the extent of the occlusive disease process can be made by measuring the systolic arterial pressure at the ankle. 7 Standard blood pressure cuffs are placed around the ankle and the arterial flow signal is monitored in the posterior tibial or dorsalis pedis artery (Fig 2). The cuff is then inflated until the arterial signal is no longer detected. With the probe still in place, the pressure is gradually lowered in the cuff until flow signals are audible once again. The point at which flow is re-established is the systolic pressure at the level of the cuff. Under normal circumstances, the systolic pressure in the ankle should be equal to or above the systolic pressure in the brachial artery. If the artery is occluded, the pressure will be lowered in the vessels distal to the occlusion.

FIG I NORMAL

SCALE - 2 cm = 1 SEC.

OBSTRUCTED

Graphic representation of audible Doppler ultrasonic flow velocity signals obtained from the posterior tibial artery of three separate patients. A - normal; B - obstructed; C - severely obstructed. SOUTHERN MEDICAL JOURNAL, Vol 68, No. 1

OFFICE TECHNICS FOR VASCULAR TESTING - Hagood et al FIG

2

Technic of obtaining ankle systolic blood pressure. The angle of the probe in relation to the long axis of the posterior tibial artery should be optimized to obtain the best signal.

An arm-to-ankle pressure gradient of more than 20 to 30 mm Hg is suggestive of occlusion at more than one level. It has been found that the ankle/arm pressure ratio correlates well with the severity of the obstructive process.4 When the ratio is one or greater, it is unlikely that significant obstruction is present. Similarly, rest pain is rare when the ankle/arm pressure ratio is greater than 0.5. There are some patients in whom the ankle pressure is normal or nearly normal and who have significant complaints of claudication. In these patients, exercise testing is an extremely valuable method of evaluation.8 When the blood flow to a limb is increased by exercise, the pressure gradient between the arm and ankle is accentuated. 2 In severe cases of obstructive vascular disease, the ankle systolic pressure may be unobtainable following exercise. Depending upon the extent and location of the disease and the type of exercise, there may be a period of up to 20 to 30 minutes before the ankle pressure returns to normal l e v e l s . T h e r o u t i n e vascular examination should include stressing the patient with some form of exercise and measuring the arm and ankle pressure immediately after the activity, using the method previously described.

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The form of exercise which is selected will depend upon the interest, requirements, and resources of the physician. In our clinic, all patients have been exercised on a level, motorized treadmill at 3 mph to the point of claudication, or a distance of 1,000 yards. This is an indication of how far the subject can walk at a marching pace on flat ground and is an objective assessment of his complaints of claudication. Strandness and B e ll 3 h a v e f o u n d t h a t b y a n g l i n g t h e treadmill at 120/, grade and at a speed of 2 mph the amount of work involved is increased and pressure gradients are accentuated. Normal subjects can walk five minutes with no difficulty and no drop in ankle pressure. A patient propelled treadmill may also be used with a metronome. The patient is instructed to step each time the metronome beats and, in this inexpensive way, the functional and provocative test of t h e p a t i e n t ’s e x e r c i s e c a p a c i t y can be carried out. Two less elaborate methods of exercising patients are available and may be used in office practice. Carter 8 has recently used active plantar and dorsiflexion of the foot a g a i n s t a resistance provided by the attendant’s hand. Alternatively, the patient can be instructed to rapidly perform toe lifts until fatigue or calf pain develops.

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These methods are less standardized than treadmill exercise, but they have the advantage of requiring no special equipment. If the initial ankle systolic pressure after exercise is equal to or higher than pre-exercise values, then the test is normal and no further measurements are required. If the initial ankle pressure is low, the measurements are repeated every minute for the next ten minutes. It should be emphasized that the Doppler survey, ankle pressure measurements, and exercise testing can be done in less than 20 minutes by paramedical office personnel. The following cases are presented to illustrate the usefulness of vascular testing methods in the clinical situation.

Case Reports Case 1. A 52-year-old man came to the medicine clinic complaining of pain involving the right leg, thigh, and buttock. The pain was precipitated by walking one block and relieved by rest. Physical examination of the right leg showed 2+ femoral and dorsalis pedis pulses and a weakly palpable posterior tibial pulse. No trophic changes or temperature differences between the two legs were observed. It was the physician’s initial impression that the slightly diminished pulses probably were not responsible for the symptoms, but the patient was referred to the vascular surgery clinic for further studies at that time. The survey with the Doppler ultrasonic velocity detector revealed abnormal signals at the right femoral, popliteal, dorsalis pedis, and posterior tibial areas. The brachial systolic pressure was 112 turn Hg. The right ankle systolic pressure was 86 mm. Hg. The patient was able to walk 115 yards at 3 mph on the treadmill. These studies suggested the presence of severe occlusive atherosclerosis of the right iliac artery. Angiography confirmed a high-grade stenosis of the entire right common iliac artery and its bifurcation. An aortoiliac endarterectomy was done subsequently. Postoperatively the patient was completely asymptomatic. Survey with the ultrasonic velocity detector showed normal flow in both lower extremities. The brachial systolic pressure was 140 mm Hg. The ankle systolic pressures were 137 turn Hg on the right and 140 mm Hg on the left.

Comment. At the time the patient was initially seen in the general medicine clinic, his complaints were suggestive of severe occlusive arterial disease. The fact that pulses were palpable in all areas, however, was confusing to the physicians who first saw him. When he was examined in the vascular laboratory using the Doppler ultrasonic velocity detector the lesion was quickly localized to the right iliac artery. The 34 turn Hg arm/ankle gradient demonstrated the severity of the problem, and the functional disability was confirmed by his performance on the treadmill. Since the patient’s job required a great deal of walking he was essentially disabled by his condition. On the basis of the objective tests, proper, diagnosis and treatment were begun. Doppler survey and ankle pressure measurements not only suggested the correct diagnosis preoperatively, but also confirmed the salutory effect of the surgical procedure post-operatively. Patients with symptoms suggestive of claudication and intact pulses may be mistakenly treated for arthritis, neuritis, or emotional problems. As was shown in this case, the correct diagnosis can be quickly and accurately made, using simple testing procedures. Case 2. A 62-year-old man with many complicated medical problems came to our clinic with complaints of pain in the right calf and night pain. Pain in the calf was precipitated by walking less than 100 ft and relieved by rest. Physical examination of the right leg showed a normal pulse in the groin. No other pulses were palpable. The right brachial systolic blood pressure was 206 mm. Hg. The right ankle systolic pressure was 78 turn Hg. Survey with the Doppler ultrasonic velocity detector showed a slightly abnormal flow signal high in the right groin. This signal became high-pitched and continuous at a point about two inches below the inguinal ligament, and low-pitched, monotonous signals were noticed distal to that level. He walked for 108 yards on the flat treadmill at 3 mph. There was a 66.5% decrease in ankle systolic pressure after exercise. An arteriogram done by the Seldinger technic showed minimal decrease in the aorta and the right iliac artery. The superficial femoral artery was occluded in Hunter’s canal. Close inspection of the bifurcation of the common femoral artery suggested significant occlusive disease, SOUTHERN MEDICAL JOURNAL, Vol 68, No. 1

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involving the origin of the deep femoral artery. Due to the patient’s poor state of general health, the right groin was explored under local anesthesia. A large occlusive plaque was located in the common femoral artery and a tight stenosis of the deep femoral orifice was observed. A common femoral and deep femoral endarterectomy were done. The patient was examined in the laboratory three months after operation. Brachial systolic pressure was 132 mm. Hg. The right ankle systolic pressure was 70 mm. Hg. He walked 1,000 yards on the flat treadmill at 3 mph with a 61% decrease in ankle pressure after exercise. Comment. The history and physical findings were not compatible with an isolated, superficial femoral artery obstruction. Disabling claudication and night pain are usually indicative of multiple arterial occlusions. The 128 mm Hg pressure gradient between the arm and ankle suggested that this was the case. Since a full femoral pulse was palpated, and only a slightly abnormal Doppler flow signal was heard in the upper common femoral artery, it was thought that the obstructed arteries were located in the thigh or calf or both. The presence of arterial signals in the popliteal artery indicated its patency. Doppler examination of the dorsalis pedis and posterior tibial arteries showed arterial flow signals similar to those obtained in the popliteal artery. This suggested no significant obstructive lesion between these levels. On the basis of these findings, the obstructive lesions could be localized to the superficial and deep femoral arteries. Results of angiography confirmed the superficial femoral artery obstruction and suggested severe stenosis of the deep femoral orifice (Fig 3). Since the hemodynamically significant lesions were confined to the thigh, it seemed logical to increase the collateral circulation distal to the occluded superficial femoral artery. Therefore, an endarterectomy of the distal common femoral artery and deep femoral artery orifice was done. It is significant to note that there were no c h a n g e s i n t h e p a t i e n t ’s p h y s i c a l examination after operation and, without vascular testing, only his testimony could be used to indicate a beneficial result.

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T h e pre -operative ankle/arm ratio was 0.38. After operation, it rose to 0.53. In addition, the patient’s exercise tolerance increased nearly tenfold. These concrete data should be used as the criteria for success or failure. FIG 3

Angiogram showing a large plaque in the common femoral artery involving the orifice of the profunda.

Case 3. A 54-year-old dentist was seen one year after bypass graft for severe aortoiliac occlusive disease. Three months after operation, he was evaluated in the laboratory. Brachial systolic pressure was 108 mm Hg. Ankle systolic pressures were 114 mm Hg on the right and 111 mm Hg on the left. Both ankle pressures increased after exercise. There were no signs o r s y m p t o m s o f ischemia. He was studied again eight months later. His pulses were intact. The arm pressure was 114 min Hg, and the ankle pressures were 126 mm Hg on the right and 96 mm Hg on the left. He walked 1000 yards on the flat treadmill at 3 mph with no symptoms. There was a 24% decrease in the left ankle pressure after exercise. Comment. This patient, though asymptomatic, is exhibiting disease progression, which will require closer f o l l o w - t i p . T h i s d i s e a s e progression could not have been detected on a clinical basis, but was readily detectable using simple vascular testing technics.